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A subset of prostate cancer displays a poor clinical outcome. Therefore, identifying this poor prognostic subset within clinically aggressive groups (defined as a Gleason score (GS) ≧8) and developing effective treatments are essential if we are to improve prostate cancer survival. Here, we performed a bioinformatics analysis of a TCGA dataset (GS ≧8) to identify pathways upregulated in a prostate cancer cohort with short survival. When conducting bioinformatics analyses, the definition of factors such as "overexpression" and "shorter survival" is vital, as poor definition may lead to mis-estimations. To eliminate this possibility, we defined an expression cutoff value using an algorithm calculated by a Cox regression model, and the hazard ratio for each gene was set so as to identify genes whose expression levels were associated with shorter survival. Next, genes associated with shorter survival were entered into pathway analysis to identify pathways that were altered in a shorter survival cohort. We identified pathways involving upregulation of GRB2. Overexpression of GRB2 was linked to shorter survival in the TCGA dataset, a finding validated by histological examination of biopsy samples taken from the patients for diagnostic purposes. Thus, GRB2 is a novel biomarker that predicts shorter survival of patients with aggressive prostate cancer (GS ≧8).

An amorphous Ta x Mn y O z layer with 1.0 nm thickness was studied as an alternative Cu diffusion barrier for advanced interconnect. The thermal and electrical stabilities of the 1.0-nm-thick Ta x Mn y O z barrier were evaluated by transmission electron microscopy (TEM) and current density-electric field (J-E) and capacitance-voltage (C-V) measurements after annealing at 400 °C for 10 h. X-ray photoelectron spectroscopy revealed the chemical characteristics of the Ta x Mn y O z layer, and a tape peeling test showed that the Ta x Mn y O z barrier between the Cu and SiO 2 layers provided better adhesion compared to the sample without the barrier. TEM observation and line profiling measurements in energy-dispersive X-ray spectroscopy after thermal annealing revealed that Cu diffusion was prevented by the Ta x Mn y O z barrier. Also, the J-E and C-V measurements of the fabricated metal-oxide-semiconductor sample showed that the Ta x Mn y O z barrier significantly improved the electrical stability of the Cu interconnect. Our results indicate that the 1.0-nm-thick Ta x Mn y O z barrier efficiently prevented Cu diffusion into the SiO 2 layer and enhanced the thermal and electrical stability of the Cu interconnect. The improved performance of the Ta x Mn y O z barrier can be attributed to the microstructural stability achieved by forming ternary Ta-Mn-O film with controlled Ta/Mn atomic ratio. The chemical composition can affect the atomic configuration and density of the Ta-Mn-O film, which are closely related to the diffusion behavior. Therefore, the 1.0-nm-thick amorphous Ta x Mn y O z barrier is a promising Cu diffusion barrier for advanced interconnect technology.